Pictured in 2008, a banded iron formation about 2.5 billion years old near Soudan Underground Mine State Park in Minnesota shows alternating layers of silica-rich (red) and iron-rich (gray) minerals.
The strikingly banded rocks scattered across the upper Midwest and elsewhere throughout the world are actually ambassadors from the past, offering clues to the environment of the early Earth more than 2 billion years ago. Continue reading… “Banded Rocks Reveal Early Earth Conditions, Changes”
